In the beginning

Heya, I am a web designer by trade and am looking at getting into mobile game development, and want to start by creating a simulation game with 8bit style graphics.

About 7 years ago I used to create RTS, Adventure & RPG games in game maker (I'm sure some of you know it) which is the reason I became a web designer now I'm getting back to my roots, GAMES!

I have read through the information on this site about starting out and am quite excited about creating a game again, and would welcome any advice anyone had about developing or learning to develop for the iPhone platform.

For most games the automatic answer would be to start by learning OpenGL, but from the look of the concept shots you have you'd probably be better off just using the normal Cocoa UI library.

In that case, I'd just say to jump right in with a book on iPhone programming. In the past, Orielly's books on Cocoa programming for the Mac have been pretty good. I'd imagine that their iPhone ones would be similarly high quality. Any good book on iPhone programming should teach you a little about Objective-C, but you really need a good basis in C programming first.

It is essentially a one room game objects are upgraded and backgrounds/objects are changed based upon the level of the upgrade, so would just be sprite switching for the screen render, do you think OpenGL would not be best for this?

I have experience in C++(beginner), PHP(intermediate), Visual Basic (ewww), but not Obj C. or C for that matter.
Will check out some of Orielly's books.

OpenGL would be a little overkill I think. The normal GUI stuff is hardware accelerated, so the drawing is reasonably quick. You can easily get 30 fps out if it for simple stuff, and your game doesn't strike me as the type that is going to demand high framerates or hundreds of sprites. It looks like your game is going to be GUI heavy instead.

The advantage of using the built in GUI stuff is that it's easier to load and display images and respond to events. Using OpenGL is a must if you need 60 fps with tons of sprites and particle effects. Cocos2D is pretty popular and hides the complexity of loading and displaying sprites using GL, but doesn't do much in terms GUIs.